o,\~"o/"7r o £.'-. t~ l~ . ~~ .. >, ."1

II .... , "1'" It~t Ft.(~~·':;·'::''; ,t OAK RIDGE NATIONAL LABORATORY

operated by UNION CARBIDE CORPORATION

for the • U.S. ATOMIC ENERGY COMMISSION J')- t

ORNL- TM-515 /

ISOTOPES DEVELOPMENT CENTER

PROGRESS REPORT

FISSION PRODUCTS

OCTOBER - NOVEMBER 1962

NOTICE This document contains information of a preliminary nature and was prepared primarily for internal use at the Oak Ridge National Laboratory. It is subject to revision or correction and therefore does not represent a final report. The information is not to be abstracted, reprinted or otherwise given public dis­semination without the approval of the ORN L patent branch, Legal and Infor­mation Control Department.

CORE Metadata, citation and similar papers at core.ac.uk

Provided by MUCC (Crossref)

r------------------------------LEGALNOTICE----------------------------~

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nor the Commission, nor any person acting an behalf of the Commission:

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ISOTOPES DEVELOPMENT CENTER

PROGRESS REPORT

FISSION PRODUCTS

October - November

Compiled by:

R. E. McHenry

Contributions by:

R. K. M:cHenry R. E. Lewis J. C. Posey

Date Issued

APR - 9 1963

OAK RIDGE NATIONAL LABORATORY Oak Ridge, Tennessee

operated by UNION CARBIDE:' CORPORATION

for the U. S. ATOMIC ENERGY COMMISSION

ORNL-TM-5l5

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TABLE OF CONTENTS

Treatment of Purex Waste . . . . . . . . . .

Extraction of Acid, Ce+++, and Ruthenium by Alamine-336 . . . . .

Differential Extract~on of Strontium Using D2EHPA

, Aluminum and

The Effect of Phosphate on Extraction With D2EHPA

Iron ..

Aluminum

2. Extraction of Ruthenium From · ~ !'i HN03 by TBP • • • •

3. Hot Cell Calorimeter . . • • .

4. Iodine-131 Adsorption From Aqueous Solutions •

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1. TREATMENT OF PUREX WASTE

Extraction of' Acid, Ce+++, and Ruthenium by Alamine-336

Preliminary data have been reportedl on the extraction of' acid f'rom Purex waste. Al$O reported were data· indicating that the only signif'icant ex­traction of fission products which occurred was that of ruthenium. Fur­ther data were required to define this extraction more fully, particularly from solutions at high pH and under conditions of differential extraction.

Two series of experiments, one using Ce+++ tracer and one using ruthenium tracer, were made on synthetic Purex waste from which the iron and Zr-Nb had been removed by successive batch extraction with D2EHPA. The distri­bution coefficients obtained are shown in Table 1.1.

Table 1.1. Extraction of Acid, Ce+++ and Ruthenium By Successive Contacting With Alamine-336

Starting Organic Phase: 25% Alamine-336, 15% 2-ethylhexanol, 60% Amsco Start~ng Aqueous P~ase: .2 ~ HN03, 1 ~ H2S04' 0.25 ~_NaN03 and tracer O/A == 1;' 5 min contact tlme

Contact Aqueous :phase Number Acid Normality 'Kfr Ce+++ Kd· Ru

1 3.36 0~0054 1.46

2 2.80 0.0046 0.28

3 2.30 0.0044 0.15

4 1.72 0.0036 0.13

5 1.00

6 0.35 0.0061 0·33

7 0.02 O~ 0067 0.81

'A batch of' feed (similar to that above) containing ruthenium tracer was extracted differentially to;a pH of 6. The conditions of extraction were:

Aqueous Volume - 1 liter

Organic Volume -3.5 liters ._-

Organic Phase Composition - 50% Alamine-336, 15% 2-ethylhexanol, 35% Amsco

Organic Flow Rate - ? literp/hr

Aqueous Recycle Rate - 28 liters/hr

lIsotopes Division Quarterly Report, April - June.. 1961, ORNL-TM-76.

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During this extraction, 81% of the ruthenium activity was removed from the aqueous phase. This value confirmed data indicating that the only signifi­cant extraction of fission products from Purex waste was that of ruthenium.

Differential Extraction of Ce+++ ,.AIUlll;inum·t and Strontium' Using D2EHPA

The synthetic waste from the ruthenium extraction described above was spiked with a Ce+++ tracer and.the acidity adjusted to 0.5 normal. The cerium was then extracte.d differentially with i M D2EHPA. Thecondi tions of the extraction were:

Aqueous Volume - 1 liter

OrganiC Volume - 3.5 liters

OrganiC Flow Rate - 1 liter/hr

Aqueous Recycle Rate - 28 liters/hr

. During the extraction, 88% of the cerium was remove.d. Under these condi­tions, promethium and europium would have been extracted quantitatively.

To extract the aluminum, the aqueous phase from the cerium extraction was adjusted to pH 1 and strontium tracer added. This aqueous phase was con­tacted with 3600 ml of 1 M D2EHPA under conditions the same as the cerium extraction. During this extraction ~8o% of the aluminum was extracted. Only 1.2% of the strontium was extracted, and therefore the removal of strontium during the cerium extraction was extremely small.

The aqueous phase from the aluminum extraction was adjusted to pH 2.5 and extracted with 2 liters of 1 M D2EHPA under the same flow conditions as the cerium and aluminum extractions" Eighty-eight percent of the stron­tium was extracted along with the remaining a~uminum. The amount of strontium extracted can be increased by contacting with an additional quantity of organic. The strontium in the organiC phase from the above extraction was readily stripped (91%) by 1/4 volume of 0.2 !:! HN03" No aluminum was detected in the strontium product.

The Effect of Phosphate on Extraction. With D2EHPA

Iron

The effect of phosphate ion in stripping iron from D2EHPA extracting solutions has been previously reported. 2 Since 'the phosphate ion reduces the distribution coefficient of iron, its presence should be considered tn any flowsheet which requires that iron be extracted from Purex \vaste (~bfJ.t}3, in:t:ng • (I~'FJ~r.e9:d.:{1:§>a.e.";,~lJ§ s:~rott:e}.I.ftQl)

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Data on the extraction of iron from synthetic Purex waste which contained varying amounts of phosphate are shown in Table 1.2 .. These, data indicate that phosphate ion lowers the distribution coefficient of iron' but shortens the time required to reach equilibrium.

Table 1.2. Extraction of Iron With 1 M D2EHPA From.801utions Containing Phosphate Ion

Aqueous Phase: 4 ~ HN03, 0.1 ~ Al+++, 0.5 ~ Fe+++,

Contact Time (min)

15

30

60

1 ~ 804--' 0.5 ~ Na+, P04'--­

Organic Phase: 1 M D2EHPA

O/A = 0.5 Forward Extra'ction

Distribution Coefficient

0.0 P04--- 0.1 M P04--- 0.2 ~ P04--~

2.00 . 1.69

4.9 2.07 1·75

5.1 2.07 1.64

0.5 ~ P04 ---

1.26

1.32

0.98

The effect of phosphate ion in reducing the time for equilibrium is shown in Tables 1.2 and 1.3. The time required to reach equilibrium when back extracting with 4 ~ HNOi is >30 min (Table 1.3), but with a concentration of as little as 0.1!i P04 -.-- the equilibrium time. is <15 min.

Contact Time

Table 1.3. Back Extraction of Iron From D2EHPA With Phosphate Ion

Aqueous Phase: 4 ~ HN03 + phosphate

Organic Phase: 1 ~ D2EHPA, 20 g/liter Fe

O/A == 1

Distribution Coefficient

(min) 0.1~· P04--- 0.2 ~ P04---

15 10.

30 10.28

1.87

1.87

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The difference between the final values of distribution coefficients in the forward and backward extraction in Tables 1.2 and 1.3 may be explained by the presence of sulphate ion during the forward extractions which would tend· to complex the iron.

Aluminum

The distribution coefficient of aluminum ion be~ween aqueou~-HN03·S01u­tions and 1 ~ D2EHPA is very high (Ka ~ 5 in 0.325 ~ HN03 ).' The equi~ librium value, however, is approached only after 10-12 hr of contacting. The back extraction of aluminum is slow even in 5 ~ EN03 (1 hr is required to reach approximate equilibrium). .. .

Several experiments using aq~eous phases of different compositions were run in an attempt to find a system which woUld reach equilibrium more rapidly and yet have sufficiently high distribution coefficients to make the extraction useful in the removal of aluminum from Purex waste follow­ing the rare earth extraction. These data ar~ shown in Tables 1.4 and 1.5. The temperature of the extraction was also varied as shown in the tables.

As in the case of iron, phosphate ion lowered the distribution coefficients and decreased the time required to reach equilibrium. An increase in tem­perature also reduced the time required to approach equilibrium.

Contact Time (min)

5

10

20

30

·40

50

60

Table 1.4. Back Extraction of Alunrlnum From 1 M D2EHPA Elf Several Acids

Q/A ~ 1

1 M PO ---I ~ HN03 ' 1 ~ H3P04 2 ~ H3P04 - ,4

(pH::! 2.5)

1·7 "",0

1·7 0.19 "",0

229 1.6 "",0

.32 1.6 "",0

12 0.19

0.065

0.057

3R. G. Deshpande and R. E. McHenry, Extraction of Aluminum· With D2EHP A (unpubli shed) •

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Contact Time' (min)

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10

20

30

40

50

60

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Table 1.5. Forward Extraction of Aluminum by 1 ~ D2EHPA From Several Solutions

O/A == 1

Aqueous Phase

Temperature == 23°C Temperature == 65°C HN03 0.1 M CH3COOH 0.1 M HCOOH HN03 0.5 M H3POlj. 0 .l' i~ HCOOH HN03

(pH == 1) (pH = 1) (pH = 1) (pH:c 2.5) (pH 1) 1 ~HN03 1 ~ H3P04 (pH = 1) (pH = 1)

0.38

0.58

0.72

0.35

0·53

0.63

O.

0.50

0 .. 63

14.

0.057

o.

0.035

--o. 0.14

0.34

0.96 2.6

0.36

22,6 8.5

0.47 304. 75.

182. 152.

1170. 229·

768. 305.

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2. EXTRACTION OF RUTHENIUM FROM 15. 7 !:! HN03 BY TBP

The extraction behavior of rutaenium from nitrate solution up to 7 molar has been reported by Fletcher.' He reports that, at higher nitric acid concentrations, the fraction of the more extractable complexes increased but that the net effect of increased acid concentration is a gradual de­crease in the overall distribution coefficient of rutheniUm.

Data on the extraction of ruthenium by TBP at acid concentration of .7 molar were required so that the separation between ruthenium and the rare earth as well as the actinide elements americium and curium could be calculated. These data shown in Table 2.1 are compatible with the con­clusions of Flet:cher -- that there are at least two species of ruthenium in the aqueous phase. (in this case predominatly the trinitrato with a

. small amount of tetra or penta-nitrato), one of which is more extractable (tetra or penta-nitrato). The conversion of the less extractable to the more extractable complex proceeds very slowly in the aqueous phase (Table 2.1, Exp. No. 1-3). According to Fletcher, some of the less extractable complex is converted to the more extractable complex in the organic When the organic phase is scrubbed with fresh aqueous phase, the conver­sion to the less extractable form takes place with a half-time of -v2 min (Table 2.1, E4p. No. 5-7).

Table 2.1. Distribution of Ruthenium . Between 10o%TBP-15.7 ~ HN03

Exp. No. Extraction O/A Contact Time Ka.

1 Forward 1 2 min 0.012

2 Forward 1 min 0.013

3 Forward 1 92 min 0.020

4 Forwarda 1. 2 min 0.012.

5 Backb 1 2 min 1.37

6 Backb 1 4 min 0.54

1 Backb 1 6 min 0.45

a Aqueous phase from Exp. No. 3 contacted with fresh organic phase. bO . rganlc phase from Exp. No. 3 contacted wi.th fresh aqueous phase.

4F• R. Bruce, J. Mo Fletcher, Ho H. Hyman and J. J. Katz, Process ChemistEY, Series III, po 135, Pergamon Press, New York, 1956.

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3. HOT CELL CALORIMETER

One of the Cs137 calorimeters. (Gamma 2) previously described5 was cali­brated and its general performance characteristics investigated. The principal difference in the Gamma 2 calorimeter and the Gamma 1 (ref 6) was the reduction in thickness of the uranium shield cup walls from 1-1/16 to 3/8 in. This change greatly reduced the heat capacity of the cup and allowed it to heat more' rapidly to the steady state temperature. Since the thinner shield cup would absorb less of the heat producing gamma rays, a precise evaluation of this factor was required.

The efficiency of gamma-ray absorption was determined in two ways. First, a small c5137 source was placed in the cup 0 Measurements of the gamma ray intensity were made at five different points on the outer surface of the cup and at the same points with the shielding cup removed. The aver­age value of the ratios of shielded to unshielded radiation measurements at the five points (0.08) is the fraction of the gamma energy not absorbed in the shield.

The second and more precise determination of the ,efficiency of absorption was made by measuring the total ,rate of absorption of the heat from a 2200-curie Cs137 source in both the Gamma land Gamma 2 calorimeter. The temperature drop per unit heat input in both calorimeters had previously been determined us an electrical heater in the cup instead of the radio-active source. The results are given in Table 3.1.

Table 3.1. Comparison of Total Energy Absorption in Calorimeters When Tested With the Same Cesium-137 Source

Gamma 1 Gamma 2 Watts Absorbed Watts Absorbed

10.169 9.656

10.193 9 .. 658

10.181 average 9.657 average

The ratio of the averages, which is the efficiency of total energy absorp­tion, is 009487- The corresponding value, calculated from the gamma absorption efficiency of 0092 with allowance for the contribution of beta radiation to the total energy, is 0.95.

5Ro E. McHenry, Fission Products, July-September 1962, ORNL-TM-451.

6J • Co Posey, To A. Butler, and P. S. Baker, "Hot Cell Calorimeter for the Routine Determination of Thermal Power Generated by Kilocurie Sources, tt

Proceedings of the Tenth Conference ,o,n Hot Laboratories and Equipment, pp 263-8, American Nuclear Society, Inc., 86 E. Randolph, Chicago, Illinois, 19620

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The Gamma 2 calorimeter approached steady state much more rapidly than Gamma 1. The rate of approach of the shaft temperature difference (m)' to the steady state value is illustrated by Table 3.2.

Table 3.2. Approach of Gamma 2 Calorimeter to Steady Statea

Time @/(6T steady state)

(min)

10 .60

40 ·90

120 ·99

200 ·999

a7-8 hr required to approach .999 steady state by Gamma 1.

4. IODINE-13l ADSORPrION FRO:M: AQUEOUS SOLUTIONS

Investigation of the use of activated charcoal to adsorb I 13l from gas streams has proved that the iodine: is highly adsorbed by the, charcoal. In the clean-up system for hot off-gases, the activated charcoal traps do not accomplish the predicted degree of iodine removal.

There are several possible factors which could account for this behavior, one of which is that the iodine may exist in several forms such as com­pounds and iodine adsorbed on particulate matter. Another possible difference in the behavior of the iodine in the laboratory and in the hot off-gas system may be due to the saturation (or actual wetting) of the activated charcoal by water vapor when the charcoal has been used over a long period of time. Several different activated charcoals were tested for their ability to adsorb I13l from aqueous solutions.

A 0.2-g amount of 200-mesh charcoal and 10 ml of water containing I13l as I2 were contacted. Several charcoals adsorbed 90+% of iodine inl hr while others required 1 week to adsorb 90+% (Table 4.1).

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Table 4.1. Fraction of 12 Adsorbing on Charcoal

Fraction Adsorbed

Carbon Structure 1 hr -1 day -1 week

Coconut (Nori te ) Crystalline .12 .. 83 - .995

Graphite (Reactor Grade) Crystalline .64 ·72 .880

RC (Pittsburg Coke & Carbon) Crystalline ·.77 ·90 ·950

RB (Pittsburg Coke & Carbon) _ Crystalline .67 ·97 .986

OL (Pittsburg Coke & Carbon) Microcrystalline ·93 .94 ·999

BL (Pittsburg Coke & Carbon) Microcrystalline .94 ·999 ·999

C (Pittsburg Coke & Carbon) Microcrystalline ·95 .98 ·993

GW (Pittsburg Coke & Carbon) Microcrystalline .98 ·993 ·999

BPL (Pittsburg Coke & Carbon) -Amorphous .48 .83 ·992

SGL (Pittsburg Coke & Carbon) Amorphous .61 .87 .992

CAL (Pittsburg Coke & Carbon) Amorphous .59 ·90 ·999

These experiments suggest that tests should be made comparing the micro­crystalline structure .charcoals with the presently used activated coconut charcoal .

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Other progress reports issued by Isotopes Development Center are:

Curium Program

Reactor- and'Cyclotron-Produced Isotopes

Radioactive Source Development

Safety Testing Program

Isotopic Separations

Target Development

Radioisotope Applications

Monthly

Bi-Monthly (odd)

Bi-Monthly (even)

Bi-Monthly (odd)

Qu~rterly

Quarterly

Quarterly

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DISTRIBUTION

1. P. S. Baker 17· E. H. Kobisk 2. E. E. Beauchamp 18. E. Lamb 3· G. E. Boyd 19· L. O. Love 4. J. C. Bresee 20. R. E. McHenry 5· S. L. Brooks 21. M. E. Ramsey 6. K. B. Brown 22. R. A. Robinson 7· T. A. Butler 23· A. F. Rupp 8. F. N. Case 24. H. E. Seagren 9· L. T. Corbin 25· M. J. Skinner

10. J. A. Cox 26. J. A. Swartout 11. D. J. Crouse 27· A. M. Weinb.erg 12. F. L. Culler 28. LaboratorY Records - RC 13. J. H. Gillette 29-30. Central Research Library 14. H. R. Gwinn 31-33· Laboratory Records 15· C. P. Keim 34~ Document Reference Section 16. M. T. Kelley

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